<?php
$params_array = array(
	'user'=>'thankwsx',
	'session_key'=>'64ebe357650b899ac5c28cafee3f9a10',
	'time'=>'1223720741'
);

$s = "51_sig_user";
echo substr($s,strlen("51_sig_"));
$app_secret = "6e233e25ccc11f8f34c15561794ec088";

    ksort($params_array);
    foreach ($params_array as $k=>$v) {
      $str .= "$k=$v";
    }
    $str .= $app_secret;
    
    echo $str."<br />";
    
    echo md5($str);
//	cur_51_sig:'60094982fc0c9951a0a9ce0be9018d1b'
?>